JPH02245568A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To make the change of driving-shaft torque smooth by obtaining the target torque at the time of attaining the first gear from the engine speed right before the engagement starting point of a hydraulic friction element and controlling oil pressure to directly attain the first gear, at the time of a gear shifting operation accompanying the start of a vehicle. CONSTITUTION:With the operation from N to D due to vehicle starting a control unit 5 detects the engagement starting time of the hydraulic friction element of an auxiliary transmission 3 and a driving torque during the engaging operation after that according to a torque detecting means 57, to detect an engagement starting point based on this driving torque. Then, by setting the target value of the torque of a driving shaft 31 from the number of revolutions of an engine 1 detected by a sensor 51 prior to the engagement starting point, feeding oil pressure to the hydraulic friction engaging element is feedback controlled so as to be conformed to the set target value via an oil pressure control portion 4, to attain the first gear stage with the smooth transmission of torque. Also, in order to contain the time from the start to the completion of engagement within a specified range, the target torque is corrected from an actual torque at the completing point of engagement by a target torque learning means. Thereby, a shift-gear shock can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an automatic transmission that reduces shift shock when switching the drive system of an automobile from a neutral state to a running state.

[Prior Art] Generally known control devices for automatic transmissions for automobiles are as follows:
Equipped with a shift lever operated by the driver, a vehicle speed detection sensor, and a throttle opening (engine load) sensor.
The gear position is automatically changed depending on the position of the shift lever, the vehicle speed, the throttle opening, etc.

Conventionally, in a control device for an automatic transmission for an automobile as described above, when the shift lever is operated from the N-D shift from the N-D shift by the driver to the drive position, the planetary gear transmission mechanism of the transmission is activated. Before shifting to 1st gear,
- It is known to prevent the occurrence of shock due to sudden transmission of torque by occasionally passing through a gear position other than first gear with a small gear ratio.

In addition, this shift control has been further improved so that one friction element is connected in advance when the shift lever is in the neutral position so that gears other than 1st gear can be smoothly obtained. This is already known from Japanese Unexamined Patent Publication No. 55-78845.

[Problem to be solved by the invention]

Conventional automatic transmission control devices are configured as described above, so during N-D shifting, the transmission must pass through a gear other than the first gear before achieving the first gear. , the shift time becomes longer, which may impair responsiveness when starting.

In addition, in order to avoid this, the first
In order to achieve a higher speed, it is necessary to control the hydraulic pressure with high precision during the coupling operation of the hydraulic friction elements, and if the hydraulic pressure setting is inappropriate, problems such as abnormal shock may occur. there were.

This invention was made in order to solve the above-mentioned problems, and it is possible to directly shift the gear position of the transmission to first gear when shifting from N-D when starting a car, and also to maintain smooth torque. The object of the present invention is to obtain a control device for an automatic transmission capable of transmission.

[Means to solve the problem]

A control device for an automatic transmission according to the present invention includes: a torque detecting means for detecting drive shaft torque; a coupling start detecting means for detecting a coupling start point of a hydraulic friction element based on the output of the torque detecting means; A target torque setting means sets the drive shaft torque from the engine rotational speed before the friction element coupling start point, and electrically controls the supply oil pressure of the hydraulic friction element so that the drive shaft torque detected by the torque sensor matches the target torque. hydraulic control means controlled by a hydraulic conversion valve; coupling completion point detection means for detecting a minimum point of input shaft rotational speed or a maximum point of drive shaft torque of the transmission to detect a coupling completion point of the hydraulic friction element; Target torque learning means that corrects and sets the target torque from the actual torque at the connection completion point of the hydraulic friction element so that the timer value that measures the time required from the connection start point to the connection completion point converges to a specified value. It has been established that

[For production]

In the N-D shift according to the present invention, the torque detection means detects the drive shaft torque at the start of coupling of the hydraulic friction elements and during the subsequent coupling operation, and based on this drive shaft torque, the coupling start point detection means detects the hydraulic The coupling start point of the friction elements is detected, the target torque setting means sets a target value of the drive shaft torque from the engine rotation speed before the coupling start point of the hydraulic friction elements, and the drive shaft torque is set by the hydraulic control means. By feedback controlling the hydraulic pressure supplied to the hydraulic friction element so as to achieve the target torque, it is possible to achieve the first gear with smooth torque transmission, and also to achieve the first gear from the connection start point of the hydraulic friction element to the connection completion point. The target torque learning means corrects the target torque from the actual torque at the point where the connection of the hydraulic friction element is completed so that the time required for the hydraulic friction element converges within a specified range, thereby facilitating matching with the engine.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing the general configuration of the main parts of this invention.
In the figure, 1 is an engine, and 2 is an input element (hereinafter referred to as a pump impeller) driven by the engine 1, which rotates internal hydraulic oil. This is a torque converter that rotates a turbine runner (referred to as a turbine runner) 22 while increasing its torque.

Reference numeral 3 denotes an auxiliary transmission, in which the shaft connected to the turbine runner 22 of the torque converter 2 is used as a transmission input shaft 31, and the shaft that transmits power to the tires is used as a transmission output shaft 32, and provides a gear ratio according to the running condition of the vehicle. It is.

Reference numeral 4 denotes a hydraulic control section for controlling the hydraulic pressure supplied to a hydraulic friction element (not shown) in the auxiliary transmission 3.

5 is a pump impeller rotation pulse 51.5 of the torque converter 2 as an input signal. The signals of the turbine runner rotation pulse 52 and the auxiliary transmission output shaft rotation pulse 53 are detected from gears and electromagnetic pickups (not shown), and there are a plurality of switches that close at selected positions of the shift lever, and the positions are determined when the switches are open or closed. A shift range signal 54 for detection; a throttle opening signal 55 connected to the accelerator pedal, which converts the engine throttle opening amount that changes in response to the amount of pedal depression into a voltage value using a potentiometer, and detects the detected throttle opening signal 55; Torque is detected by a magnetostrictive torque sensor 57 (described in Japanese Patent Application No. 182713/1982) which is installed on the axis of the transmission input shaft 31 and detects the torsional stress applied to the same axis by using, for example, the magnetostrictive effect. The transmission input shaft torque signal 5B, which is converted into a voltage value according to the voltage value and output, is input, and based on this information, the gear stage suitable for the vehicle's driving condition is determined, and the gear stage necessary for shifting the gear stage is determined. Hydraulic control signal 5
This is a control unit whose main component is a microcomputer that outputs the signal 6 as an output signal to a solenoid valve (not shown) in the hydraulic control device 4.

Figure 2 shows double and onion planetary gear set 1.
FIG. 3 is a schematic diagram of an auxiliary transmission 3 with three forward speeds using a set of gears.

In this FIG. 2, 20 is driven by an engine,
The engine crankshaft 31 rotates together with the pump impeller 21 of the torque converter 2, and is also the output shaft of the torque converter that rotates together with the turbine runner 22 of the torque converter 2 and transmits driving force to the auxiliary transmission 3. It is the human power axis of the machine.

33 is a double pinion planetary gear set,
This planetary gear cent 33 is the forward sun gear 3
4, a reverse sun gear 35, a ring gear 36, a seat pinion 37, a long pinion 3B, and a carrier 39.

The forward sun gear 34 is connected to the rear clutch C2, and the reverse sun gear 35 is connected to the front clutch CI.
The output shafts 31 of the torque converter 2 are connected to the output shafts 31 of the torque converter 2, respectively.

Also, Bl is a low reverse brake, B2 is a second brake, 3C is a transmission case, and a low reverse brake.
The reverse brake Bl fixes and releases the carrier 39 to the case 3C, the second brake B2 fixes and releases the reverse sun gear 35 to the case 3C, and the ring gear 36 is connected to the output shaft 32 of the auxiliary transmission 3. There is.

FIG. 3 is a block diagram of the hydraulic control circuit of this automatic transmission, and 40 in the figure is an oil pump provided on the crankshaft 20 of the engine 1.

41 is a pressure regulator valve for regulating the oil pressure generated by the oil pump 40 as line pressure, 42 is a shift control valve that is directly connected to the shift lever, and 43 to 45 are low reverse brakes B.
This is a duty solenoid valve for controlling, for example, the hydraulic pressure supplied to the second brake B2 and the front clutch CI by a duty controller.

When moving forward, hydraulic pressure is supplied to the C2 carrier clutch through the shift control valve, and the clutch is engaged.

The combination of the coupling operations of the friction elements in each gear stage is such that the rear clutch c2 is engaged in forward motion, the low reverse brake Bi is in 1st gear, and the second brake B is in 2nd gear.
At the 2.3rd speed, the front clutch C1 is in the engaged state.

When reversing, the front clutch C1 and low reverse brake B1 are engaged.

Next, FIG. 4 shows the effect of the N-D shift embodiment.

This will be explained along the flowchart of FIG. 5 and the time chart of FIG. 6.

Figure 4 is the main flowchart, and in step 31,
The position of the shift lever operated by the driver is detected by, for example, a bit pattern of the shift range signal 54, and in step S2, the throttle opening amount is read, and in step s3, the input shaft 20 of the torque converter 2 is detected. Output shaft 3
1 and the output shaft 32 of the auxiliary transmission 3, the rotation pulses 51 to 53 of each shaft detected from the configuration of a gear (not shown) and an electromagnetic pickup are measured by the control unit 5 to measure the average pulse period at each fixed sampling period, The engine rotational speed (pump rotational speed of the torque converter 2) K9 and the input/output shaft rotational speeds N1 and N of the auxiliary transmission 3 (equivalent to vehicle speed) are calculated.

In step S4, the torque signal 58 output as a voltage value from the torque sensor 57 is A/D converted and detected as a transmission input shaft torque T.

In step S5, it is determined whether the drive shaft is in the neutral state or in the running state depending on the shift lever position. For example, when the car is stopped and the shift lever is in the N range, the process proceeds to step S6. In this step S6, the solenoid valves 43 to 45 are kept fully closed.

When the shift lever is in the N range, the shift control valve 42, which operates in conjunction with the shift lever, cuts off the supply of hydraulic pressure to each friction element, so that the drive shaft is placed in a neutral state.

On the other hand, the driver tried to start the car by pressing the shift lever to N.
, if the operation is in a position other than the P (parking) range, the process proceeds to step S7, in which it is determined whether the shift type is an N-D shift, and if it is not an N-D shift, another shift is performed in step S8. If the N-D shift is selected, the process proceeds to step S9, and the N-D shift is executed.

An execution flowchart of the N-D shift is shown in FIG. 5. In FIG. 5, in step S10, the shift process is determined based on the phase value, and processing is performed for each phase.
At the time of N-D shift command, it is phase -0, and Stesive S
ll, the process of S12 is performed only once.

In step S1, in order to fill oil into the piston cylinder in preparation for the start of engagement of the low reverse brake B1, a predefined duty rate DBI of the solenoid valve 43 is set.
Outputs I. In step S12, the shift process is changed to phase-1 and the process returns to the main routine.

Next, when the shift process moves to phase l, step S13
In step 313, the transmission input shaft torque T1
The connection start point of the low reverse brake Bl is detected depending on whether the level of the torque reaches a predetermined torque value TI, and if T L < T t, the process returns to the main routine and the low reverse brake Bl is connected. wait.

When the connection start point of the low reverse brake B1 is detected from T1≧T, the processes from step 314 to step S16 are performed only once.

In step S14, the transmission input shaft torque T at the time of achieving l-speed, which is the engagement completion point, is calculated from the engine rotational speed N before the engagement start point of the low reverse brake B2 as T, K,, N, (kgf-m )
...(1), and set the final target torque T, □1.

In this equation (1), K1 is a torque capacity coefficient at the time of stalling, and is a constant determined from the torque ratio.

Further, in step 515, the low reverse brake B1
Clear the timer (
t-0) and started.

In step 316, the shift process is set to phase 2, the transition of the shift process is set, and the process returns to the main routine.

Subsequently, when the shift process moves to phase-2, the process proceeds to step S17, and in step S17, the minimum point of the transmission input shaft rotational speed N1 is detected or the transmission input shaft torque T is detected.
The connection completion point of the low reverse brake Bl is determined based on whether , has reached the maximum point.

If the determination result has not reached the connection completion point, the process advances to step S18, and in step 51B, the target value Tt□ of the transmission input shaft torque is set to T&mttz+-'r++(T&mi+'r+)/
, a・t ...(2), calculated for each control cycle,
The target torque T is increased in a ramp-like manner so that the final target torque TtH□ is reached at the specified time t+s. The actual torque T is the target torque T. For example, the duty ratio DB, , of the solenoid valve 43 is set to follow the well-known P, 1. It is calculated based on the D@i1 formula and output as the hydraulic pressure control signal 56.

If the determination result in step S17 is that the connection completion point of the low reverse brake B1 is detected, steps 319 to
The process of step 322 is performed to complete the ND shift.

In step 319, the timer is stopped and the time t1 required for shift process phase-2 is measured.

In step S20, whether or not the target torque T set in step S14 is appropriate is determined using the formula (1) if the shift time t1 is not within a predetermined range of the shift time t. 1 is added to the constant determined from the stall torque capacity coefficient and torque ratio of the torque converter performance. Correction calculation is performed using the ratio of the actual shaft torque T at the completion point and the final target torque TLNII (T, , /T%, 1.) Then, a new constant is set by learning, in preparation for the next N-D shift.

In step S21, in order to make the oil pressure of the low reverse brake B1 line pressure, the duty rate of the solenoid valve 43 is output at 100%, the solenoid valve is kept fully open, and 1st speed is achieved, and the phase is cleared in step S22. Then, the N-D shift operation is completed.

Fig. 6 shows a time chart of the N-D shift process.
Figure (C) shows the engine rotation speed Nz and transmission input shaft rotation speed N1, Figure 6 (B) shows the transmission input shaft torque T and target torque T1□, and Figure 6 (e) shows the control phase of the shift process. This is what is shown.

In the above embodiment, the torque sensor is provided on the transmission input shaft, but it may be provided anywhere on the drive shaft.

Further, although the rotational speed of the engine is calculated from the rotational pulse detected from the configuration of the gear and the electromagnetic pickup provided on the input shaft of the torque converter 2, it may also be calculated from the ignition pulse of the engine.

Furthermore, although the output shaft torque of the torque converter 2 was detected by a torque sensor, it is also possible to use the torque calculated from the input shaft and output shaft rotational speeds of the torque converter 2 based on the torque converter performance curve. good.

Further, although the target value of the transmission manual shaft torque was determined as a function of the engine rotational speed, the same effect can be obtained even if it is determined from the relationship between the throttle opening amount and the intake pipe negative pressure.

〔Effect of the invention〕

As described above, according to the present invention, during the shift operation associated with the start of the car, the target torque at the time of achieving the first gear is calculated and estimated from the engine rotation speed immediately before the connection start point of the hydraulic friction element, A ramp-shaped target torque waveform is set with this as the final target torque, and the coupling start point of the hydraulic friction element is detected by the output of the torque detection means, so that the subsequent driving torque will be at the target value. Since it is configured to directly achieve 1st speed by controlling the oil pressure of the hydraulic friction element, it is possible to smoothly control the drive shaft torque change, and the shift shock is small. A faster gear position can be obtained, and the responsiveness of starting is improved.

In addition, by appropriately setting the target torque using the learning function, stable and highly accurate shift characteristics can be obtained.
This has the effect of facilitating matching with the engine.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the main part configuration of an automatic transmission control device according to an embodiment of the present invention, and Fig. 2 shows three forward speeds using a double pinion type planetary gear set 1&lI applied to the above embodiment. Schematic diagram of the auxiliary transmission, 3rd
The figure is a block diagram of the hydraulic control circuit of the automatic transmission applied to the above embodiment, FIG. 4 is a flowchart showing the main flow of the above embodiment, and FIG. 5 is a flowchart showing the N-D shift execution flow of the above embodiment. Flowchart, FIG. 6 is a time chart at the time of executing the ND shift. l...engine, 2...torque converter, 3...
- Auxiliary transmission, 4... Hydraulic control section, 5... Control unit, 40... Oil pump, 43-45... Deity solenoid valve, Bl... Low reverse brake, 2...・Seven cant brake! ...Front mouth, 2...Rear clutch, ...Torque sensor. In addition, in the figures, the same symbols indicate the same or equivalent parts.

Claims (1)

[Claims] In a control device for a hydraulic automatic transmission that determines a driver's intention based on a shift lever position and controls a drive shaft from a neutral state to a running state, a torque detection means for detecting the drive shaft torque; coupling start point detection means for detecting a coupling start point of the hydraulic friction elements based on the output of the hydraulic friction elements; target torque setting means; hydraulic control means for controlling the hydraulic pressure supplied to the hydraulic friction element by an electro-hydraulic valve so that the drive shaft torque detected by the torque detection means matches the target torque; and an input to a transmission. A connection completion point detection means for detecting a connection completion point of the hydraulic friction element by detecting a minimum point of the shaft rotational speed or a maximum point of the driving wheel torque, and a connection completion point of the hydraulic friction element from the connection start point to the connection completion point. and target torque learning means for correcting and setting the target torque from the actual torque at the connection completion point so that the timer value measured by the timer means converges within a specified value. Characteristic automatic transmission control device.